1. Field of the Invention
The present invention relates to a method, system and network elements for transmission of encoded signals between nodes of a telecommunications network and the decoding and processing of the encoded signal at the receiving node as well as to computer software for coordinating transmission, decoding and processing in an optimum way. The present invention also relates to a description useful for decoding an encoded bit stream, a method of using such a description so as to decode and process the bit stream in a destination terminal. The invention also relates to an electronic device designed for implementing such a method of generating such a description. The invention also relates to a transmission system comprising a transmitter and a receiver, said transmitter having means for implementing such a method of generating an encoded bit stream and a description therefor from a source signal.
2. Description of the Related Technology
Network environments have undeniably grown to an important communication tool in our society. The increasing trend to user mobility and associated ubiquitious multimedia access, leads to a proliferation of a heterogeneous set of terminals, e.g., high-resolution televisions, high-end graphics workstations, PCs, game consoles and low-end portable devices.
Cost is the driving force behind this differentiation: the lower the cost to the end user, the more technological restrictions are imposed (e.g., constraints in silicon size and power consumption), and the lower the access bandwidth and processing capabilities of the appliance. Furthermore, with the advent of multiple connected environments, one single terminal can be simultaneously connected to different servers, therefore consuming content with potentially highly, dynamically and stochastically changing characteristics.
Network Quality of Service (Network QoS), guaranteeing a service quality under constrained network conditions, has since several years got a lot of attention. However, Quality of Service dedicated to the Terminal (Terminal QoS), where the application is matched to the processing power of the terminal, is a relatively new topic of research.
Today, whereas streaming video is common practice, the streaming of 3D content remains rare, or even nonexistent. When decoding and rendering 3D content, the workload on the consumer's platform heavily varies over several orders of magnitude with the viewing conditions. As mostly only a part of the textured 3D objects is visible at any given time, streaming and/or decoding only the visible regions of the texture will reduce instantaneous bandwidth and/or platform workload. When the viewing conditions change, the newly visible parts can be streamed and/or decoded as they gradually become visible. Consequently, the required network bandwidth as well as the required workload for decoding and rendering textured 3D content are spread over time while minimizing the perceived quality loss. This process is known as view-dependent texture decoding [D. Cohen-Or, Y. Mann, S. Fleishman, “Deep Compression for Streaming Texture Intensive Animations,” Proceedings of the SIGGRAPH 1999 annual conference on Computer graphics, pp. 261-267, 1999.].
Within the MPEG-4 multimedia compression standard [“The MPEG-4 Audio-Visual Compression Standard, Text of ISO/IEC 14496-5/FPDAM1,” ISO/IEC JTC1/SC29/WG11/MPEG99/N3309, Noordwijkerhout, March 2000.], tools are available for coding 3D content. In particular, MPEG-4 provides a scalable, wavelet based, compression tool for textures, called Visual Texture Coding (VTC) [I. Sodagar, H. J. Lee, P. Hatrack, Y. Q. Zhang, “Scalable Wavelet Coding for Synthetic/Natural Hybrid Images,” IEEE Transactions on Circuits and Systems for Video Technology, Vol. 9, No. 2, pp. 244-254, March 1999.].